Manufacture of metallic-coated sheets and plates



Aug. 7, 1928.

J. MCFETRIDGE IANUFACTURE OF IETALLIC COATED SHEETS AND PLATES Filed Jan. 1'7, 192'! 2 Sheets-Sheet 1 v Inventor: JOEEPH /7 FET,e/0a;,

la'dnesses Aug. 7, 19m

J. M FETRIDGE IANUFACTURE OF METALLIC COATED SHEETS AND PLATES Filed Jan. 17, 1927 z sm g -snet" 2 V firlnesses:

JOSEPH fi /"fre/aa jzavenfor;

PatentedAug. i a

'nonor m'aw JERSEY.

i 1 7 1,679,435 f U I ED' ST TEs PATENT JOSEPH mern'mmen, or vanmsnea rr, rEnnsxLvamA, assrenoa TO almmcan snnn'r AND rm PLATE COMPANY, or PITTSBURGH, rnnnsnvama, acoarommurac'runn;or METALLIC-CO TED snna'rs 5mm,

' U Application filed January 17. 1923. Serial 110461534.

. and, has for one of its objectsthe provi-' sion of'a method for treating the sheets and plates which will prevent rapidoxidation of the sheets and plates to ferric form after pickling.

Another object is to.'prov1de a method wherein the sheets and plates may be cleaned by passing through a diluted solution of sulfuric acidprior to being passed into the flux side of the coating pot, instead of being passed through a hydrochloric acid bath which is 'much more expensive than sulfuric acid;

A further object is to provide a novel method whereby the sheets will carry liquid flux into the flux side of the coating pot to maintain a constant body of flux .in the ot. p A still further object is to provide a novel form of apparatus for carrying out my novel method described and claimed herein.

Heretofore the usual practice in preparing sheets and plates for galvanizing, tinning and the like, has been to place from fifty'to several hundred sheets, depending upon the gage and size of the sheets, side by ShdB in a rack, then submerge the rack containing the sheets in a hot acid bath. After the sheets have been cleaned or pickled, the rack containing the sheets is removed from the acid bath and immediately submerged in a tank of cold running water, for the purpose of removing the free acid and soluble iron salts from the sheets.

At best the above method provided imperfectly cleaned and washed sheets, and the surface of such sheets rapidly oxidized to the ferric form which materially increased the cost of the subsequent treatment ste s. v

, After the sheets were washed as described above, they were submerged in a bath .of diluted hydrochloric acid, and then passed into the flux side of the coating pot. In this last operation the ferric hydroxide on the sheets was only partly removed, so that the sheets entered the'coating pot with ferric hydroxide still on their surfaces.- Heretocoatin fore ammonia chloride crystals have added'from time to time to the flux in the conditlon. The imperfectly 'washed sheets resulting from the method described aboveare entered into the flux side of the coating.

u le iron salts entering the flux,.are removed in the flux and the iron combines with coat-- mg material or metal to form" an 'I alloy, which in galvanizing is called .dross since ,it is an alloy of zinc andiron.

The present method consists in. part in completely cleaning or pickling the sheets and lates by submersion in ahot pickle or acid ath, then submergingi the,cleaned or pickled sheets or plates 111 31 cold solutionof inorganic salts until cooled to approximately TlOO egrees Fahrenheit or less, then removmg the sheets and plates from the inorganic salt solution. The sheets and plates treated as above may be stored a reasonable length of time without the formation of ferric 'hy-' droxide, or, if such sheets are exposed separately, the sheets or' plates will dry fromthe heat absorbed from the hot pickle liquor, and a film of ferrous salts will form on the sheets so as to provide, a protective coating, whereby the sheets or plates may be stored for hours without the formation of ferric.

hydroxide.

After the sheets or plates cleaned and immersed in the, cold solution have been pot to maintain the' flux in active of soluble inorganic salts, the sheets are next passed through a diluted sulfuric acid bath having a strength of from 5 degrees B. to

15 degrees B., to remove any ferrous hy-- droxide that may be formed thereon, and

the finally cleaned plates are then passed between suitable sprays of either hot or cold water which thoroughly wash both sidesof the sheets or plates to remove all acid and when they pass between the washing sprays, they are free from all solid foreign matter,

soluble iron salts. The sheets and plates. I

but are wet with diluted sulfuric acid and soluble iron' salts, all of which are removed or washed off by the water sprays. After the sheets pass between the water sprays and are washed, they are then passed into a flux tank containing a body of liquid flux,

' to bein such as a solution of ammonia chlorid,'zinc chlorid, zinc ammonia chlorid, and'the like, heated to from 160 to 180 degrees Fahrenheit. The sheets as they pm through the flux in the flux tank are wetted with the flux and also preheated by the heated'flux and are then pased directly into the flux.

side of the coating pot, and the sheets due wetted with fluxfrom the flux sulfates and the term inorganic salts as used t roughout this specification and claims is used to define the abovementioned salts.

In the drawings- Figures 1 and 1 show a longitudinal sectional elevation .through apparatus used in carrying out the ste s of the method subsequent to the remove of the plates from the solution of inorganic salts.

Figu through the washing tank taken on the line 11-11 of Figure 1.

In carrying out this invention in ractice the sheets or plates after being pic ed and cooled in the cold solution of inorganic salts, such as the cold spent pickle liquor (ferrous sulfate), or other sulfates and chlorids, are

removed from the bath of inorganic salts,

and piled or stacked on a transfer wa n or .truckA to be transferred to the location of the remainder of the apparatus necessary to carry out the remaining steps of the invention;

The transfer wagon A, after being loaded with sheets or plates B from the inorganic salt bath,'is'moved into position to have its load fed into the bite of a pair of feed rolls 2 mounted. at the entrance end of an acid bath tank 3 which is preferably filled with a bath of diluted sulfuric acid.

The sheets or plates B will be manually or otherwise fed from the truck A into the bite 'of the feed rolls 2 and the rolls 2 will feed the plates betweenguides 4, which will guide the plates or sheets down through the acid bath and up into the bite of a pair of feed --rolls- 5 mounted-between the acid bath tank 3 and'a washing or spraying space 6.

A pair of horizontally arranged and spaced sprays? are mounted in the tank 6 and a. guide, support or rack, composed of aced bars 8, is arranged to guide the sheets or plates between the spra s 7 so thatboth top and bottomsides of't e plates will be thoroughly washed.

The rolls 5 will feed the sheets or plates re 2 is a transverse sectional elevation including the step of removin merging said sheets and gsolutiton of soluble inorganic salts, and holdfrom the tank 3 along the guide rack comosed of bars 8, between the sprays 7 and which are mounted between wash tank 6 and a flux tank 12.

. The flux tank 12 is normally filled with a into the bite of a pair of feed rolls 14.

The feed rolls 10 are adapted to feed the sheets or plates through the flux tank and into the bite of the feed rolls 14, which in turn feed the sheets or plates into the bite of feed rolls 16 on the flux side X of a,coating pot Y of standard design. The plates as they pass through and from the flux in the tank 12, will pick up and carry suflicient liquid flux to maintain the body of flux in the flux side of the coating pot Y constant, thereby eliminating the necessity of adding flux in crystal form to the flux in the flux side of the coating pot, which practice results in from forty to fifty per cent. of the added flux being lost through volatilization.

\Vh1le I have described a certain specific arrangement of the steps of my novel method and certain specific apparatus for nto the bite of a third pair of feed rolls 10, i

carrying out part of such method, it will be 1. The method of preparing sheets and plates for galvanizing, tinning and the like,

including the step of removm the sheets and plates from the hot pic c bath and without washing submerging said sheets and plates in a cold solution of soluble inorganic salts.

2. The method of preparing sheets llU plates for galvanizing, tinning and the like,

the sheets and plates from the hot pick e bath and without washing submer ing said sheets and plates in cold spent ic e l quor. Y 3. The method 0 preparing sheets. and lates for galvanizing, tinning and the like, including the following steps, submerging the sheets and plates in a hot acid pickling :bath, removing said sheets and plates from said pickling bath and without washing sublates in a cold ing'said-s'heets and plates in said solution of soluble inorganic salts until said sheets and plates are cooled to approximately degrees Fahrenheit.

4. The method of preparing sheets and plates for galvanizing, tinning and the like,

including the following steps, submerging said pickling bath and without washing subat sheets and plates in a hot acid pickling hath, removing said sheets and plates from merging said sheets and plates in a cold spent pickle liquor bath, and holding said s eets and plates in said cold s ent pickle liquor bath until said sheets an plates are cooled to approximately 100 degrees Fahrenheit.

5. The method of preparing sheets and plates for galvanizing, tinning'and the like.

consisting of submerging the sheets and plates in a hot acid. pickling bath, removing said sheets and plates from saidpickling bath and without washing submergin 'said 1 sheets and plates in a cold solution 0 $0111- ble inorgamc salts, holding said sheets and P plates in said solution of soluble inorganic salts until said sheets and plates are cooled to approximatel '100 degrees Fahrenheit,

.' removlng said s eets and plates fromtsaid solution of soluble inor merging said sheets an plates in an acid solution to remove any ferrous hydroxide, then washing said sheets and lates to remove all soluble ferrous salts. an then assing said washed sheets I through a body of flux prior to entering 'said sheets and plates into the coatingpot. a 6. The method of preparing sheets and plates for galvanizing, tinnin and the like,

, consisting of submerging t e sheets and sheets and plates in a col plates in a hot acid pickling bath, removing said sheets and plates fromsaid .pickling bath and without washing sub'mergm said solution 0 soluble-inorganic, -salts','holding said sheets'and lution of solubleinorganic sa1ts,.then sub- ,merging said sheets-and plates in an acid solution to remove any ferrous hydroxide,

y then washing said sheets. andplates to remove all soluble ferrous'salts, and then passing said washed sheets and plates immedi ately through a body of liquid flux prior to,

entering said sheets and plates into the flux v side of the coat' sheets and m 0t.- i 7. The method 5f preparing sheets 'and plates for galvanizing, tinning and the like, consisting of submergin'g the sheets and plates'in a hot' acid pickling bath, removing said sheets and plates from said picklingbath and without washing submerging said plates in said solution ofsoluble inorganic "salts until said sheets and plates are cooled f to approximately 100 degrees Fahrenheit, removing said sheets and platesfrom said solution of soluble inorganic salts, then sub merging said sheets and plates-in a sulfuric then'passingsaid washed sheets lad nicsalt-s, then sub-' and plates 1 immediately theiilux side of ing said sheets and of thecoating ot. I p

10. The met od of preparing sheets and; plates for galvanizing, tinnin' and the like .,con'sisting-of submerging .t e sheetsj, an i 1 plates in a hot acid pickling'jbath, removingsaid: sheets and .plates "from .said bath {and without washing suhmergmgsaid 1 sheets and plates-in a cold bath of s ent". pickle liquor, holding said sheets andp ates lates in a cold, solution of solu-; ble inorganic salts, holding said sheets and acid solution to; remove ferrous hydrox-o ide, then washi'n saids'heets and plates to remove all solube ferrous salts, then;

passing said washedsheets and platesimm'eiately through. a body of liquid flux prior tov enteringsaid sheets. and plates into the flux side ofthe coating pot;- f

8'. The method of preparing and plates for galvanizing, tinning "and the like consisting of submerging the sheets an I said sheets and platesfrom said picklin bath, and without washing submergin sai sheets and plates in a cold solution o soluble inorganic salts, holding said sheets and plates in said solution of soluble inorganic salts until said sheets and plates are'cooled I to approximately 100 degrees Fahrenheit, re-

;moving said sheets and-plates from'said solution of soluble'inorganic salts, 'then sub v merging said sheets and plates in a sulfuric acid solution to remove any ferrous hydrox-' I. I ide then spraying both sides of said sheets an plates to remove all soluble ferrous salts andthen passingisaidwashed sheets an 1 plates immediately through a body of liquid flux prior to entering said sheets and plates into the flux side of the coating 'pot.- a '9. The method of preparing sheets an plates for galvanizing, tinning and the like, consisting of submerging the sheets and plates in a hot acid pickling bath, removing said sheetsand platesfrom said pickling bath and without washing submergingsaid sheets and plates in a cold solution of soluble inorsaid solution of soluble-inorganic sa saidsheets and plates are cooled to approxij I matel 100 degrees-Fahrenheit, removing all soluble ferrous salts, andthenpassing said washed sheets and .plates immediately through a body of liquidfiuxpriortojenteri'cklirig plates into. the flux side in said bath until said sheets and plates-are cooled to approximately 100 degrees Fahren heit,--'remo'v1ng said sheets and, lates from c said bath, then submergingsai sheets and plates in an acidsolution to remove any ferrous hydroxide, then washi said sheets and plates to remove allsoluble" errous salts, and

plates in a hot acidpickling fbath", removing I i00 ganic salts, holdin said sheets and lates in 4 ts until,

.acid solution to remove any ferrous immediately through a body of flux prior to entering said sheets and plates into the flux side of the coating pot.

11. The method of preparing sheets and plates for galvanizing, tinning and the like, consisting of submerging the sheets and plates in a hot acid pickling bath, removing said sheets and plates from said pickling bath and without washing submergin said sheets and plates in a cold bath of spent pickleliquor, holding said sheets and plates in said bath until said sheets and plates are vcooled to approximately 100 degrees Fahrenheit, removing said sheets and plates from said bath, then submerging said sheets and plates in han ydroxide, then washing said sheetsj and plates to remove all soluble ferrous salts, and then passing said washed sheets and plates immediately through a body of liquid-flux prior to entering said'sheets and plates into the flux side of the coating pot, whereby said sheets and plates will carry a quantity of flux'from said body, into the flux in the flux side of the coating pot.

l2. The method of preparing sheets and plates for galvanizing, tinning and the like, consisting of submerging the sheets and platesin a hot acid pickling bath, removing said sheets and plates from said pickling bath and without washin submerging said sheets and plates in a ooldmth of spent pickle liquor, holding said sheets and plates in said bath until said sheets and plates are cooled to approximately 100 degrees Fahrenheit, removing said sheets and plates from said bath, then submerging said sheets and plates in a sulfuric acid solution to remove any ferrous hydroxide, then washing said sheets and plates to remove all soluble-ferrous salts, and then passing said washed sheets and plates immediately through a body of liquid flux prior to entering said sheets and plates into the flux on the flux side of the coating pot, whereby said sheets and plates will carry a quantit of flux from said liquid flux body into t e flux on the flux side of said coating pot.

13. The method of preparing sheets and plates for galvanizing, tinning and the like, consisting of submerging the sheets and plates in a hot acid pickling bath, re-

moving said sheets and plates from said pickling bath and without washing .sub-

merging said sheets and plates in a cold bath of spent pickle liquor, holding said sheets and plates in said bath until said sheets and plates are cooled to approximately 100 degrees Fahrenheit, removing said sheets and plates from said bath, then submerging said sheets and plates in a sulfuric acid solution to remove any ferrous hydroxide, then spraying both sides of said sheets and plates to remove all soluble ferrous salts, and then passing said washed sheets and plates immediately through a body of liquid flux prior to entering said sheets. and plates into the fiux on the flux side of the coating pot, whereby said sheets and plates will carry a quantity of flux from said liquid flux body into the flux on the flux side of said coating pot.

14. The method of preparing sheets and plates for galvanizing, tinning and the like,

consisting of submerging the sheets and plates in a hot acid pickling bath, removing said sheets and plates. from said pickling bath and without washing submerging said sheets and plates in acold solution of soluble inorganic salts, holding said sheets and plates in said solution of soluble inorganic salts until said sheets and plates are cooled to approximately 100 degrees F ahrcnheit, removing said sheets and plates from said solution of soluble inorganic salts, then exposing said sheets and plates separately to permit said sheets and plates to dry and form a protective coating of ferrous salts thereon, then submerging said sheets and plates in an acid solution to remove any ferrous hydroxide, then washing said sheets and plates to remove all soluble ferrous salts, and then passing said washed sheets and plates immediately through a body of flux prior to entering said sheets and plates into the flux side of the coating pot.

15. The method of preparing sheets and plates for galvanizing, tinning and the like, consisting of submerging the sheets and plates in a hot acid pickling bath, removing said sheets and plates from said pickling bath and without washing submerging said sheets and plates in a cold bath of spent pickle liquor, holding said sheets and plates in said bath until said sheets and plates are cooled to approximately 100 do grees Fahrenheit,removing said sheets and plates from said bath, then exposing said sheets and plates separately to permit said sheets and plates to dry and form a protective coating of ferrous salts thereon, then submerging said sheets and plates in an acid solution to remove any ferrous hydroxide, then washing said sheets and plates to remove all soluble ferrous salts, and then passing said washedsheets and plates iin vmediately through a body of flux prior to entering said sheets and plates into the flux side of the coating pot.

JOSEPH MCFETRIDGE. 

